1 .\" Copyright (c) 2007, 2008 Marcel Moolenaar
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32 .Nd "control utility for the disk partitioning GEOM class"
49 .\" ==== BOOTCODE ====
53 .Op Fl p Ar partcode Fl i Ar index
100 .\" ==== RESTORE ====
135 utility is used to partition GEOM providers, normally disks.
136 The first argument is the action to be taken:
137 .Bl -tag -width ".Cm bootcode"
140 Add a new partition to the partitioning scheme given by
142 The partition begins on the logical block address given by the
145 Its size is given by the
148 SI unit suffixes are allowed.
153 options can be omitted.
154 If so they are automatically calculated.
155 The type of the partition is given by the
158 Partition types are discussed below in the section entitled
159 .Sx "PARTITION TYPES" .
161 Additional options include:
163 .It Fl a Ar alignment
166 utility tries to align
174 The index in the partition table at which the new partition is to be
176 The index determines the name of the device special file used
177 to represent the partition.
179 The label attached to the partition.
180 This option is only valid when used on partitioning schemes that support
183 Additional operational flags.
184 See the section entitled
185 .Sx "OPERATIONAL FLAGS"
186 below for a discussion
191 Dump a partition table to standard output in a special format used by the
194 .\" ==== BOOTCODE ====
196 Embed bootstrap code into the partitioning scheme's metadata on the
200 or write bootstrap code into a partition (using
204 Not all partitioning schemes have embedded bootstrap code, so the
206 option is scheme-specific in nature (see the section entitled
211 option specifies a file that contains the bootstrap code.
212 The contents and size of the file are determined by the partitioning
216 option specifies a file that contains the bootstrap code intended to be
217 written to a partition.
218 The partition is specified by the
221 The size of the file must be smaller than the size of the partition.
223 Additional options include:
226 Additional operational flags.
227 See the section entitled
228 .Sx "OPERATIONAL FLAGS"
229 below for a discussion
234 Commit any pending changes for geom
236 All actions are committed by default and will not result in
238 Actions can be modified with the
240 option so that they are not committed, but become pending.
241 Pending changes are reflected by the geom and the
243 utility, but they are not actually written to disk.
246 action will write all pending changes to disk.
249 Create a new partitioning scheme on a provider given by
253 option determines the scheme to use.
254 The kernel must have support for a particular scheme before
255 that scheme can be used to partition a disk.
257 Additional options include:
260 The number of entries in the partition table.
261 Every partitioning scheme has a minimum and maximum number of entries.
262 This option allows tables to be created with a number of entries
263 that is within the limits.
264 Some schemes have a maximum equal to the minimum and some schemes have
265 a maximum large enough to be considered unlimited.
266 By default, partition tables are created with the minimum number of
269 Additional operational flags.
270 See the section entitled
271 .Sx "OPERATIONAL FLAGS"
272 below for a discussion
277 Delete a partition from geom
279 and further identified by the
282 The partition cannot be actively used by the kernel.
284 Additional options include:
287 Additional operational flags.
288 See the section entitled
289 .Sx "OPERATIONAL FLAGS"
290 below for a discussion
293 .\" ==== DESTROY ====
295 Destroy the partitioning scheme as implemented by geom
298 Additional options include:
301 Forced destroying of the partition table even if it is not empty.
303 Additional operational flags.
304 See the section entitled
305 .Sx "OPERATIONAL FLAGS"
306 below for a discussion
311 Modify a partition from geom
313 and further identified by the
316 Only the type and/or label of the partition can be modified.
317 To change the type of a partition, specify the new type with the
320 To change the label of a partition, specify the new label with the
323 Not all partitioning schemes support labels and it is invalid to
324 try to change a partition label in such cases.
326 Additional options include:
329 Additional operational flags.
330 See the section entitled
331 .Sx "OPERATIONAL FLAGS"
332 below for a discussion
335 .\" ==== RECOVER ====
337 Recover a corrupt partition's scheme metadata on the geom
339 See the section entitled
341 below for the additional information.
343 Additional options include:
346 Additional operational flags.
347 See the section entitled
348 .Sx "OPERATIONAL FLAGS"
349 below for a discussion
354 Resize a partition from geom
356 and further identified by the
359 New partition size is expressed in logical block
360 numbers and can be given by the
365 option is omitted then new size is automatically calculated
366 to maximum available from given geom
369 Additional options include:
371 .It Fl a Ar alignment
374 utility tries to align partition
380 Additional operational flags.
381 See the section entitled
382 .Sx "OPERATIONAL FLAGS"
383 below for a discussion
386 .\" ==== RESTORE ====
388 Restore the partition table from a backup previously created by the
390 action and read from standard input.
391 Only the partition table is restored.
392 This action does not affect the content of partitions.
393 After restoring the partition table and writing bootcode if needed,
394 user data must be restored from backup.
396 Additional options include:
399 Destroy partition table on the given
401 before doing restore.
403 Restore partition labels for partitioning schemes that support them.
405 Additional operational flags.
406 See the section entitled
407 .Sx "OPERATIONAL FLAGS"
408 below for a discussion
413 Set the named attribute on the partition entry.
414 See the section entitled
416 below for a list of available attributes.
418 Additional options include:
421 Additional operational flags.
422 See the section entitled
423 .Sx "OPERATIONAL FLAGS"
424 below for a discussion
429 Show current partition information for the specified geoms, or all
430 geoms if none are specified.
431 The default output includes the logical starting block of each
432 partition, the partition size in blocks, the partition index number,
433 the partition type, and a human readable partition size.
434 Block sizes and locations are based on the device's Sectorsize
437 Additional options include:
440 For partitioning schemes that support partition labels, print them
441 instead of partition type.
443 Show provider names instead of partition indexes.
445 Show raw partition type instead of symbolic name.
449 Revert any pending changes for geom
451 This action is the opposite of the
453 action and can be used to undo any changes that have not been committed.
456 Clear the named attribute on the partition entry.
457 See the section entitled
459 below for a list of available attributes.
461 Additional options include:
464 Additional operational flags.
465 See the section entitled
466 .Sx "OPERATIONAL FLAGS"
467 below for a discussion
471 .Sh PARTITIONING SCHEMES
472 Several partitioning schemes are supported by the
475 .Bl -tag -width ".Cm VTOC8"
477 Apple Partition Map, used by PowerPC(R) Macintosh(R) computers.
482 Traditional BSD disklabel, usually used to subdivide MBR partitions.
484 This scheme can also be used as the sole partitioning method, without
486 Partition editing tools from other operating systems often do not
487 understand the bare disklabel partition layout, so this is sometimes
489 .Dq dangerously dedicated .
495 The Logical Disk Manager is an implementation of volume manager for
496 Microsoft Windows NT.
501 GUID Partition Table is used on Intel-based Macintosh computers and
502 gradually replacing MBR on most PCs and other systems.
507 Master Boot Record is used on PCs and removable media.
513 option adds support for the Extended Boot Record (EBR),
514 which is used to define a logical partition.
516 .Cm GEOM_PART_EBR_COMPAT
517 option enables backward compatibility for partition names
519 It also prevents any type of actions on such partitions.
521 An MBR variant for NEC PC-98 and compatible computers.
526 Sun's SMI Volume Table Of Contents, used by
536 Partition types are identified on disk by particular strings or magic
540 utility uses symbolic names for common partition types so the user
541 does not need to know these values or other details of the partitioning
545 utility also allows the user to specify scheme-specific partition types
546 for partition types that do not have symbolic names.
547 Symbolic names currently understood are:
548 .Bl -tag -width ".Cm ms-ldm-metadata"
550 The system partition dedicated to second stage of the boot loader program.
551 Usually it is used by the GRUB 2 loader for GPT partitioning schemes.
552 The scheme-specific type is
553 .Qq Li "!21686148-6449-6E6F-744E-656564454649" .
555 The system partition for computers that use the Extensible Firmware
557 In such cases, the GPT partitioning scheme is used and the
558 actual partition type for the system partition can also be specified as
559 .Qq Li "!c12a7328-f81f-11d2-ba4b-00a0c93ec93b" .
561 A partition that contains a FAT16 filesystem.
562 The scheme-specific type is
566 A partition that contains a FAT32 filesystem.
567 The scheme-specific type is
573 partition subdivided into filesystems with a
576 This is a legacy partition type and should not be used for the APM
578 The scheme-specific types are
583 .Qq Li "!516e7cb4-6ecf-11d6-8ff8-00022d09712b"
588 partition dedicated to bootstrap code.
589 The scheme-specific type is
590 .Qq Li "!83bd6b9d-7f41-11dc-be0b-001560b84f0f"
595 partition dedicated to swap space.
596 The scheme-specific types are
597 .Qq Li "!FreeBSD-swap"
599 .Qq Li "!516e7cb5-6ecf-11d6-8ff8-00022d09712b"
600 for GPT, and tag 0x0901 for VTOC8.
604 partition that contains a UFS or UFS2 filesystem.
605 The scheme-specific types are
606 .Qq Li "!FreeBSD-UFS"
608 .Qq Li "!516e7cb6-6ecf-11d6-8ff8-00022d09712b"
609 for GPT, and tag 0x0902 for VTOC8.
613 partition that contains a Vinum volume.
614 The scheme-specific types are
615 .Qq Li "!FreeBSD-Vinum"
617 .Qq Li "!516e7cb8-6ecf-11d6-8ff8-00022d09712b"
618 for GPT, and tag 0x0903 for VTOC8.
622 partition that contains a ZFS volume.
623 The scheme-specific types are
624 .Qq Li "!FreeBSD-ZFS"
626 .Qq Li "!516e7cba-6ecf-11d6-8ff8-00022d09712b"
627 for GPT, and 0x0904 for VTOC8.
629 A partition that is sub-partitioned by a Master Boot Record (MBR).
630 This type is known as
631 .Qq Li "!024dee41-33e7-11d3-9d69-0008c781f39f"
634 A basic data partition (BDP) for Microsoft operating systems.
635 In the GPT this type is the equivalent to partition types
640 The scheme-specific type is
641 .Qq Li "!ebd0a0a2-b9e5-4433-87c0-68b6b72699c7"
644 A partition that contains Logical Disk Manager (LDM) volumes.
645 The scheme-specific types are
648 .Qq Li "!af9b60a0-1431-4f62-bc68-3311714a69ad"
650 .It Cm ms-ldm-metadata
651 A partition that contains Logical Disk Manager (LDM) database.
652 The scheme-specific type is
653 .Qq Li "!5808c8aa-7e8f-42e0-85d2-e1e90434cfb3"
656 A partition that contains a NTFS or exFAT filesystem.
657 The scheme-specific type is
661 A partition that contains a VMware File System (VMFS).
662 The scheme-specific types are
665 .Qq Li "!aa31e02a-400f-11db-9590-000c2911d1b8"
667 .It Cm vmware-vmkdiag
668 A partition that contains a VMware diagostic filesystem.
669 The scheme-specific types are
672 .Qq Li "!9d275380-40ad-11db-bf97-000c2911d1b8"
674 .It Cm vmware-reserved
675 A VMware reserved partition.
676 The scheme-specific type is
677 .Qq Li "!9198effc-31c0-11db-8f-78-000c2911d1b8"
679 .It Cm vmware-vsanhdr
680 A partition claimed by VMware VSAN.
681 The scheme-specific type is
682 .Qq Li "!381cfccc-7288-11e0-92ee-000c2911d0b2"
686 The scheme-specific attributes for EBR:
687 .Bl -tag -width ".Cm active"
691 The scheme-specific attributes for GPT:
692 .Bl -tag -width ".Cm bootfailed"
696 stage 1 boot loader will try to boot the system from this partition.
697 Multiple partitions can be marked with the
704 Setting this attribute automatically sets the
709 stage 1 boot loader will try to boot the system from this partition only once.
710 Multiple partitions can be marked with the
719 This attribute should not be manually managed.
722 stage 1 boot loader and the
723 .Pa /etc/rc.d/gptboot
730 The scheme-specific attributes for MBR:
731 .Bl -tag -width ".Cm active"
735 The scheme-specific attributes for PC98:
736 .Bl -tag -width ".Cm bootable"
742 supports several partitioning schemes and each scheme uses different
744 The bootstrap code is located in a specific disk area for each partitioning
745 scheme, and may vary in size for different schemes.
747 Bootstrap code can be separated into two types.
748 The first type is embedded in the partitioning scheme's metadata, while the
749 second type is located on a specific partition.
750 Embedding bootstrap code should only be done with the
755 The GEOM PART class knows how to safely embed bootstrap code into
756 specific partitioning scheme metadata without causing any damage.
758 The Master Boot Record (MBR) uses a 512-byte bootstrap code image, embedded
759 into the partition table's metadata area.
760 There are two variants of this bootstrap code:
765 searches for a partition with the
769 section) in the partition table.
770 Then it runs next bootstrap stage.
773 image contains a boot manager with some additional interactive functions
774 for multi-booting from a user-selected partition.
776 A BSD disklabel is usually created inside an MBR partition (slice)
780 .Sx "PARTITION TYPES"
782 It uses 8 KB size bootstrap code image
784 embedded into the partition table's metadata area.
786 Both types of bootstrap code are used to boot from the GUID Partition Table.
787 First, a protective MBR is embedded into the first disk sector from the
790 It searches through the GPT for a
793 .Sx "PARTITION TYPES"
794 section) and runs the next bootstrap stage from it.
797 partition should be smaller than 545 KB.
798 It can be located either before or after other
800 partitions on the disk.
801 There are two variants of bootstrap code to write to this partition:
804 .Pa /boot/gptzfsboot .
807 is used to boot from UFS partitions.
811 partitions in the GPT and selects one to boot based on the
816 If neither attribute is found,
822 .Pq the third bootstrap stage
823 is loaded from the first partition that matches these conditions.
826 for more information.
829 is used to boot from ZFS.
830 It searches through the GPT for
832 partitions, trying to detect ZFS pools.
833 After all pools are detected,
835 is started from the first one found.
837 The VTOC8 scheme does not support embedding bootstrap code.
838 Instead, the 8 KBytes bootstrap code image
840 should be written with the
844 option to all sufficiently large VTOC8 partitions.
847 option could be omitted.
849 The APM scheme also does not support embedding bootstrap code.
850 Instead, the 800 KBytes bootstrap code image
852 should be written with the
854 command to a partition of type
856 which should also be 800 KB in size.
857 .Sh OPERATIONAL FLAGS
858 Actions other than the
862 actions take an optional
865 This option is used to specify action-specific operational flags.
870 flag so that the action is immediately
874 to have the action result in a pending change that can later, with
875 other pending changes, be committed as a single compound change with
878 action or reverted with the
882 The GEOM PART class supports recovering of partition tables only for GPT.
883 The GPT primary metadata is stored at the beginning of the device.
884 For redundancy, a secondary
886 copy of the metadata is stored at the end of the device.
887 As a result of having two copies, some corruption of metadata is not
888 fatal to the working of GPT.
889 When the kernel detects corrupt metadata, it marks this table as corrupt
890 and reports the problem.
894 are the only operations allowed on corrupt tables.
896 If the first sector of a provider is corrupt, the kernel can not detect GPT
897 even if the partition table itself is not corrupt.
898 The protective MBR can be rewritten using the
900 command, to restore the ability to detect the GPT.
901 The copy of the protective MBR is usually located in the
905 If one GPT header appears to be corrupt but the other copy remains intact,
906 the kernel will log the following:
907 .Bd -literal -offset indent
908 GEOM: provider: the primary GPT table is corrupt or invalid.
909 GEOM: provider: using the secondary instead -- recovery strongly advised.
913 .Bd -literal -offset indent
914 GEOM: provider: the secondary GPT table is corrupt or invalid.
915 GEOM: provider: using the primary only -- recovery suggested.
924 will report about corrupt tables.
926 If the size of the device has changed (e.g.,\& volume expansion) the
927 secondary GPT header will no longer be located in the last sector.
928 This is not a metadata corruption, but it is dangerous because any
929 corruption of the primary GPT will lead to loss of the partition table.
930 This problem is reported by the kernel with the message:
931 .Bd -literal -offset indent
932 GEOM: provider: the secondary GPT header is not in the last LBA.
935 This situation can be recovered with the
938 This command reconstructs the corrupt metadata using known valid
939 metadata and relocates the secondary GPT to the end of the device.
942 The GEOM PART class can detect the same partition table visible through
943 different GEOM providers, and some of them will be marked as corrupt.
944 Be careful when choosing a provider for recovery.
945 If you choose incorrectly you can destroy the metadata of another GEOM class,
946 e.g.,\& GEOM MIRROR or GEOM LABEL.
950 variables can be used to control the behavior of the
953 The default value is shown next to each variable.
954 .Bl -tag -width indent
955 .It Va kern.geom.part.check_integrity : No 1
956 This variable controls the behaviour of metadata integrity checks.
957 When integrity checks are enabled, the
959 GEOM class verifies all generic partition parameters obtained from the
961 If some inconsistency is detected, the partition table will be
962 rejected with a diagnostic message:
963 .Sy "GEOM_PART: Integrity check failed (provider, scheme)" .
964 .It Va kern.geom.part.ldm.debug : No 0
965 Debug level of the Logical Disk Manager (LDM) module.
966 This can be set to a number between 0 and 2 inclusive.
967 If set to 0 minimal debug information is printed,
968 and if set to 2 the maximum amount of debug information is printed.
969 .It Va kern.geom.part.ldm.show_mirrors : No 0
970 This variable controls how the Logical Disk Manager (LDM) module handles
972 By default mirrored volumes are shown as partitions with type
975 .Sx "PARTITION TYPES"
977 If this variable set to 1 each component of the mirrored volume will be
978 present as independent partition.
980 This may break a mirrored volume and lead to data damage.
983 Exit status is 0 on success, and 1 if the command fails.
985 Create a GPT scheme on
987 .Bd -literal -offset indent
988 /sbin/gpart create -s GPT ada0
991 Embed GPT bootstrap code into a protective MBR:
992 .Bd -literal -offset indent
993 /sbin/gpart bootcode -b /boot/pmbr ada0
998 partition that can boot
1002 partition, and install bootstrap code into it.
1003 This partition must be larger than the bootstrap code
1008 .Pa /boot/gptzfsboot
1010 but smaller than 545 kB since the first-stage loader will load the
1011 entire partition into memory during boot, regardless of how much data
1012 it actually contains.
1013 This example uses 88 blocks (44 kB) so the next partition will be
1014 aligned on a 64 kB boundary without the need to specify an explicit
1015 offset or alignment.
1016 The boot partition itself is aligned on a 4 kB boundary.
1017 .Bd -literal -offset indent
1018 /sbin/gpart add -b 40 -s 88 -t freebsd-boot ada0
1019 /sbin/gpart bootcode -p /boot/gptboot -i 1 ada0
1022 Create a 512MB-sized
1024 partition to contain a UFS filesystem from which the system can boot.
1025 .Bd -literal -offset indent
1026 /sbin/gpart add -s 512M -t freebsd-ufs ada0
1029 Create an MBR scheme on
1031 then create a 30GB-sized
1033 slice, mark it active and
1037 .Bd -literal -offset indent
1038 /sbin/gpart create -s MBR ada0
1039 /sbin/gpart add -t freebsd -s 30G ada0
1040 /sbin/gpart set -a active -i 1 ada0
1041 /sbin/gpart bootcode -b /boot/boot0 ada0
1048 label) with space for up to 20 partitions:
1049 .Bd -literal -offset indent
1050 /sbin/gpart create -s BSD -n 20 ada0s1
1053 Create a 1GB-sized UFS partition and a 4GB-sized swap partition:
1054 .Bd -literal -offset indent
1055 /sbin/gpart add -t freebsd-ufs -s 1G ada0s1
1056 /sbin/gpart add -t freebsd-swap -s 4G ada0s1
1059 Install bootstrap code for the
1062 .Bd -literal -offset indent
1063 /sbin/gpart bootcode -b /boot/boot ada0s1
1066 Create a VTOC8 scheme on
1068 .Bd -literal -offset indent
1069 /sbin/gpart create -s VTOC8 da0
1072 Create a 512MB-sized
1074 partition to contain a UFS filesystem from which the system can boot.
1075 .Bd -literal -offset indent
1076 /sbin/gpart add -s 512M -t freebsd-ufs da0
1081 partition to contain a UFS filesystem and aligned on 4KB boundaries:
1082 .Bd -literal -offset indent
1083 /sbin/gpart add -s 15G -t freebsd-ufs -a 4k da0
1086 After creating all required partitions, embed bootstrap code into them:
1087 .Bd -literal -offset indent
1088 /sbin/gpart bootcode -p /boot/boot1 da0
1091 Create a backup of the partition table from
1093 .Bd -literal -offset indent
1094 /sbin/gpart backup da0 > da0.backup
1097 Restore the partition table from the backup to
1099 .Bd -literal -offset indent
1100 /sbin/gpart restore -l da0 < /mnt/da0.backup
1103 Clone the partition table from
1109 .Bd -literal -offset indent
1110 /sbin/gpart backup ada0 | /sbin/gpart restore -F ada1 ada2
1124 .An Marcel Moolenaar Aq marcel@FreeBSD.org